Leader Election in Anonymous Rings: Franklin Goes Probabilistic

We present a probabilistic leader election algorithm for anonymous, bidirectional, asynchronous rings. It is based on an algorithm from Franklin, augmented with random identity selection, hop counters to detect identity clashes, and round numbers modulo 2. As a result, the algorithm is finite-state, so that various model checking techniques can be employed to verify its correctness, that is, eventually a unique leader is elected with probability one. We also sketch a formal correctness proof of the algorithm for rings with arbitrary size

Isospin splitting in heavy baryons and mesons

A recent general analysis of light-baryon isospin splittings is updated and extended to charmed baryons. The measured $\Sigma_c$ and $\Xi_c$ splittings stand out as being difficult to understand in terms of two-body forces alone. We also discuss heavy-light mesons; though the framework here is necessarily less general, we nevertheless obtain some predictions that are not strongly model-dependent.Comment: 12 pages REVTEX 3, plus 4 uuencoded ps figures, CMU-HEP93-

Granular discharge and clogging for tilted hoppers

We measure the flux of spherical glass beads through a hole as a systematic function of both tilt angle and hole diameter, for two different size beads. The discharge increases with hole diameter in accord with the Beverloo relation for both horizontal and vertical holes, but in the latter case with a larger small-hole cutoff. For large holes the flux decreases linearly in cosine of the tilt angle, vanishing smoothly somewhat below the angle of repose. For small holes it vanishes abruptly at a smaller angle. The conditions for zero flux are discussed in the context of a {\it clogging phase diagram} of flow state vs tilt angle and ratio of hole to grain size

Cerebellar Cortical Degeneration in Cattle Poisoned With Solanum spp. in South America: An Epidemiological, Clinicopathological, Pathological, and Toxicological Review

Cattle that consume Solanum bonariense L (= Solanum fastigiatum Willd.) or Solanum paniculatum L. develop a typical cerebellar cortical degeneration characterized by periodic episodes of ataxia, hypermetria, hyperesthesia, head and thoracic limb extension, opisthotonus, nystagmus, and falling to the side or backward. Histological lesions include vacuolation, degeneration, and loss of Purkinje cells. Axonal spheroids, microcavitations, and other changes of Wallerian degeneration in cerebellar granular layer and white matter are also observed. Neurotoxic compounds in Solanum spp. causing neurologic dysfunction in ruminants were not definitively elucidated. The same Solanaceae species are extensively used with culinary purposes or for the treatment of liver and gastrointestinal disorders as hangovers in humans. In the present paper, we review the epidemiology, clinical signs, and pathological hallmarks of poisoning by Solanum —S. bonariense L. (=S. fastigiatum Willd.) and S. paniculatum—with emphasis in histopathology, ultrastructural, and lectin- and immuno-histochemical changes in spontaneous and experimentally poisoned cattle in South America. The current knowledge of the pathogenesis of these bovine cerebellar cortical degenerations is discussed, and some advances in botanical and toxicological aspects of these Solanaceae species are presented, taking into account the potential risk of human poisoning.Fil: Verdes, Jose M.. Universidad de la República; UruguayFil: Riet Correa, Franklin. Federal University of Campina Grande; BrasilFil: Medeiros, Rosane M.T.. Federal University of Campina Grande; BrasilFil: Moraña, Antonio. Universidad de la República; UruguayFil: Battes, Daniel. Universidad de la República; UruguayFil: Dehl, Virginia. Universidad de la República; UruguayFil: Borteiro, Claudio. Universidad de la República; UruguayFil: Gimeno, Eduardo Juan. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sant’Ana, Fabiano J.F.. Universidade Federal de Goiás; BrasilFil: Barros, Claudio S.L.. Federal University of Santa Maria; BrasilFil: Barros, Servero S.. Federal University of Santa Maria; Brasi

A major shift to the retention approach for forestry can help resolve some global forest sustainability issues

Approximately 85% of the global forest estate is neither formally protected nor in areas dedicated to intensive wood production (e.g., plantations). Given the spatial extent of unprotected forests, finding management approaches that will sustain their multiple environmental, economic, and cultural values and prevent their conversion to other uses is imperative. The major global challenge of native forest management is further demonstrated by ongoing steep declines in forest biodiversity and carbon stocks. Here, we suggest that an essential part of such management—supplementing the protection of large reserves and sensitive areas within forest landscapes (e.g., aquatic features)—is the adoption of the retention approach in forests where logging occurs. This ecological approach to harvesting provides for permanent retention of important selected structures (e.g., trees and decayed logs) to provide for continuity of ecosystem structure, function, and species composition in the postharvest forest. The retention approach supports the integration of environmental, economic, and cultural values and is broadly applicable to tropical, temperate, and boreal forests, adaptable to different management objectives, and appropriate in different societal settings. The widespread adoption of the retention approach would be one of the most significant changes in management practice since the onset of modern high-yield forestry.Fil: Lindenmayer, D.B.. The Australian National University,; AustraliaFil: Franklin, J.F.. University of Washington; Estados UnidosFil: Lõhmus, A.. University of Tartu; EstoniaFil: Baker, S.C.. University of Tasmania; AustraliaFil: Bauhus, J.. Albert Ludwigs University of Freiburg; AlemaniaFil: Beese, W.. University of Vancouver; CanadáFil: Brodie, A.. No especifíca;Fil: Kiehl, B.. Swedish University of Agricultural Sciences; SueciaFil: Kouki, J.. University of Eastern Finland; FinlandiaFil: Martínez Pastur, Guillermo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: Messier, C.. Université du Québec a Montreal; CanadáFil: Neyland, M.. University of Tasmania; AustraliaFil: Palik, B.. No especifíca;Fil: Sverdrup Thygeson, A.. Norwegian University of Life Sciences; NoruegaFil: Volney, J.. Canadian Forest Service; CanadáFil: Wayne, A.. No especifíca;Fil: Gustafsson, L.. Swedish University of Agricultural Sciences; Sueci

Can forest management based on natural disturbances maintain ecological resilience?

Given the increasingly global stresses on forests, many ecologists argue that managers must maintain ecological resilience: the capacity of ecosystems to absorb disturbances without undergoing fundamental change. In this review we ask: Can the emerging paradigm of natural-disturbance-based management (NDBM) maintain ecological resilience in managed forests? Applying resilience theory requires careful articulation of the ecosystem state under consideration, the disturbances and stresses that affect the persistence of possible alternative states, and the spatial and temporal scales of management relevance. Implementing NDBM while maintaining resilience means recognizing that (i) biodiversity is important for long-term ecosystem persistence, (ii) natural disturbances play a critical role as a generator of structural and compositional heterogeneity at multiple scales, and (iii) traditional management tends to produce forests more homogeneous than those disturbed naturally and increases the likelihood of unexpected catastrophic change by constraining variation of key environmental processes. NDBM may maintain resilience if silvicultural strategies retain the structures and processes that perpetuate desired states while reducing those that enhance resilience of undesirable states. Such strategies require an understanding of harvesting impacts on slow ecosystem processes, such as seed-bank or nutrient dynamics, which in the long term can lead to ecological surprises by altering the forest's capacity to reorganize after disturbance

Regional Adoption of Business-to-Business Electronic Commerce in China: Role of E-Readiness

Adoption of B2B e-commerce is a powerful driver of economic success in developed and developing countries. However, adoption rates in developing countries lag far behind. This paper draws on the Perceived eReadiness Model and research on the influence of inter-organizational relationships and economic-cultural contexts to explain the importance of three factors—inter-organizational power dependence, cooperativeness, and regional economic-cultural differences—for achieving higher levels of Internet-based Electronic Data Interchange (EDI) in the developing country of China. We employ survey data to empirically test both the individual and joint influence of these factors. The findings suggest that beyond intra-organizational and external factors, managers and policy makers wanting to promote Internet-based EDI adoption in developing countries must also account for the inter-organizational relationships of firms and the economic and cultural circumstances of the regions in which they operate

SU(4) Chiral Quark Model with Configuration Mixing

Chiral quark model with configuration mixing and broken SU(3)\times U(1) symmetry has been extended to include the contribution from c\bar c fluctuations by considering broken SU(4) instead of SU(3). The implications of such a model have been studied for quark flavor and spin distribution functions corresponding to E866 and the NMC data. The predicted parameters regarding the charm spin distribution functions, for example, \Delta c, \frac{\Delta c}{{\Delta \Sigma}}, \frac{\Delta c}{c} as well as the charm quark distribution functions, for example, \bar c, \frac{2\bar c}{(\bar u+\bar d)}, \frac{2 \bar c}{(u+d)} and \frac{(c+ \bar c)}{\sum (q+\bar q)} are in agreement with other similar calculations. Specifically, we find \Delta c=-0.009, \frac{\Delta c}{{\Delta \Sigma}}=-0.02, \bar c=0.03 and \frac{(c+ \bar c)}{\sum (q+\bar q)}=0.02 for the \chiQM parameters a=0.1, \alpha=0.4, \beta=0.7, \zeta_{E866}=-1-2 \beta, \zeta_{NMC}=-2-2 \beta and \gamma=0.3, the latter appears due to the extension of SU(3) to SU(4).Comment: 10 RevTeX pages. Accepted for publication in Phys. Rev.